Trading was expected to remain tentative and volatile as investors wait to see if Bernanke offers more support for the U.S. economy when he delivers a highly anticipated speech at a conference later Friday in Jackson Hole, Wyoming.

Worries that the U.S. could be headed for another recession has in recent weeks caused huge volatility in equities, bonds and foreign exchange.

On Thursday, the U.S. government reported an increase in the number of people applying for unemployment benefits last week. The Labor Department said applications rose to 417,000, the highest in five weeks.

The Dow Jones industrial average closed down or 1.5 percent at 11,149.82. The S&P 500 index fell 1.6 percent to 1,159.27. The Nasdaq fell 1.9 percent to 2,419.63.